This project is devoted to test the hypothesis that brain tumors in high risk groups could be triggered by the presence of a germ line mutation in tumor suppressor genes, specifically in p53. The study will consist of screening several groups of pediatric and adult brain tumor patients including those with first degree relatives suffering from other malignancies, those with multiple primary neoplasms and infants under two years of age. Once the incidence of p53 germ line mutations in these high risk populations is determined, further studies will analyze the molecular and cellular evidence supporting or challenging the hypothesis that these mutations play an important role in the development of brain tumors in these selected populations.